For the most part, trees are able to take care of themselves pretty well. However, since we take them out of their native environments and plant them where they may, or may not, have grown by themselves, there are a couple of things we can do to help them out on a seasonal basis.
Illustration of using the flat tree guard tied loosely around the trunk. © 2017 McNeill’s Tree Service
If you live in an area that actually gets winter, you know, cold temperatures, snow…that kind of thing, you need to consider protecting your trees’ trunks.
The candidates most likely to need this are young, newly transplanted trees. Why? Because their bark is thin. Thin-barked trees are particularly susceptible to sunscald which is an environmentally-caused, abiotic, injury which can be seriously damaging.
The problem is created in the winter when the sun is lower in the sky and typically occurs on the south and southwest sides of trees. The sun heats up the bark, the sap in the cambium flows, the sun goes behind a cloud or sets creating a sudden drop in temperature which can cause lethal freezing. The damaged tissue is now susceptible to pathogenic organisms as well as having sustained the initial physical injury. The damage is seldom seen for months if not years as the dead and dying bark does not slough off the tree immediately. When finally noticed, this is seen as a “sudden” event by the homeowner but the damage actually occurred in the past.
There is no “cure”. (See Blog on Trees Don’t Heal, They Seal) Prevention, though, goes a long way. In late fall, install a protective shield on the south/southwest side of the trunk. It may go all the way around the trunk if using one of the white tubes sold for this purpose. If your tree has grown too big for the tubes (generally sold in 2” and 3” sizes), you can use flat, white corrugated protectors and tie them on.
Whereas this is generally only necessary for young trees until their bark is sufficiently thick enough to withstand normal winters, there are a few trees that remain susceptible their entire lives. Species such as Mountain ash trees, Sorbus spp., and the extremely popular Autumn Blaze maple, Acer freemonii, ‘Autumn Blaze’, are two examples. Protection for trees which stay sensitive to sunscald can be accomplished by planting understory shrubs and perennials on the south/southwest side of the tree which will give it winter protection as well.
© 2017 McNeill’s Tree Service